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Ahh, so the 12z Euro continues from the 0z with a possible N Atlantic block setting up. This looks to pull the PV into SE Canada and build that ridge back into Greenland. This helps my idea of a mid-December pattern change.

Question; I know I've heard knowledgeable folks say that some of our best storms come during a pattern breakdown but it seems that typically happens when a favorable pattern is about to buckle and go unfavorable. Does it work the other way around. That is if the Euro stays consistent should we be looking in the 10 - 15 day range for a possible storm? I know I'm kind of asking a weenie question here but just curious.

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FWIW--- JB, Will have his latest winter update out the end of this week, But He said that he would probably be adjustments down on the snow east of the mountains in the Mid Atlantic, He never has gave the Southeast any hope for this winter.... And now He's fixing to jerk the rug out from under the Mid Atlantic. lol :drunk:

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Question; I know I've heard knowledgeable folks say that some of our best storms come during a pattern breakdown but it seems that typically happens when a favorable pattern is about to buckle and go unfavorable. Does it work the other way around. That is if the Euro stays consistent should we be looking in the 10 - 15 day range for a possible storm? I know I'm kind of asking a weenie question here but just curious.

Eh, I suppose it could happen.

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FWIW--- JB, Will have his latest winter update out the end of this week, But He said that he would probably be adjustments down on the snow east of the mountains in the Mid Atlantic, He never has gave the Southeast any hope for this winter.... And now He's fixing to jerk the rug out from under the Mid Atlantic. lol :drunk:

JB got one winter right in the past 5 years and that was '09

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Question; I know I've heard knowledgeable folks say that some of our best storms come during a pattern breakdown but it seems that typically happens when a favorable pattern is about to buckle and go unfavorable. Does it work the other way around. That is if the Euro stays consistent should we be looking in the 10 - 15 day range for a possible storm? I know I'm kind of asking a weenie question here but just curious.

RaleighWX's case studies on NC snowstorms indicate a -NAO is more important for Hickory type (W NC events), compared to more of a diffuse signal seen in RAH storms. Good question, I like to look for inflection points, change in concave up vs concave down (& vice-versa) with the NAO specifically. Almost textbook setup would be a Greenland block retrograding into central Canada, and down into the northern Plains, after it did its magic, and put a vortex about 20-30 degrees south. Big storms often happen in that setup. Extreme type tele-indices are usually unfavorable, and one looks for at-least one, PNA for example, to give a little bit, or NAO, etc... So much more comes into play though then just teleconnections, but they are a valuable tool when looking at the overall pattern that may evolve, remember though, these are still climate model forecasts (and pattern changes have been known to lag in what we see 10-14 days out). I am big on inflection points rather than the often termed "relaxing," sure others may differ, just my 2 cents.

From Allan's NC Winter Storm page

Raleigh

The 500mb pattern most common in these 20 events is one where there is pronounced ridging over and above Alaska and also in western North America leading to cross-polar flow and a +PNA configuration, but unlike Hickory, the -NAO signature is very diffuse and much less than what is shown in the Hickory data. This could indicate the ideal pattern for big RDU snows is a strong +PNA configuration and a transitional NAO pattern where the value is around neutral.

Hickory

The 500mb pattern most common in these 20 events is one where there is pronounced ridging over and above Alaska and also in western North America leading to cross-polar flow and a +PNA, also there are

12z ECMWF ens mean (note orienation of "the" PV, also on our side of the Pole)

12zECMWFENS500mbHeightAnomalyNH240.gif

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Good disco WeatherNC. I agree. I'm big on seeing alarm bells go off in the Southeast when there is either a -NAO west based or a PNA pattern with some kind of blocking in western Canada (or eastern near Baffin Island), or a split flow which is most likely in Nino's. The one caveat that may save some (snow lovers) in this upcoming season might be the closed off/upper lows that move across, with not much of either of the regular indicies present. There's been a few here and there in an otherwise bad pattern that can still give a major snowfall in a pretty bad pattern. Last couple of years was textbook for us though, but sometimes the active flow can work some winter magic and even in a warm pattern.

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DT speaks: "The super warm November of 2011 was caused in my opinion by the development of a large 500 Low– a POLAR VORTEX — over Siberia which moves across the Bering sea into Alaska during the month. At the same time a Ridge in the North Pacific was trying to expand and push north towards the Aleutian islands and the south coast of Alaska. These two forces cause the Pacific jet stream to “COMPACT” : we could be seen by noting the very strong wind speed velocities at 200 MB during the month of November over the north Pacific. At times the speed were up to 200 knots. This extremely fast Pac jet not only ensure a persistent trough over the West Coast but it also cut off the flow of any sort of cold air getting into central or Southern Canada."

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DT speaks: "The super warm November of 2011 was caused in my opinion by the development of a large 500 Low– a POLAR VORTEX — over Siberia which moves across the Bering sea into Alaska during the month. At the same time a Ridge in the North Pacific was trying to expand and push north towards the Aleutian islands and the south coast of Alaska. These two forces cause the Pacific jet stream to “COMPACT” : we could be seen by noting the very strong wind speed velocities at 200 MB during the month of November over the north Pacific. At times the speed were up to 200 knots. This extremely fast Pac jet not only ensure a persistent trough over the West Coast but it also cut off the flow of any sort of cold air getting into central or Southern Canada."

What super warm November is he talking about? unsure.gif

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What super warm November is he talking about? unsure.gif

I can't find the map but most of the east torched in November, parts of the SE were an exception. Areas in the Ohio valley and the northeast were way, way above normal.

Here are three cites in the northeast and this was a common theme in the east this month.

through the 28th

DC + 2.6

NYC + 3.7

BOS + 4.9

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DT at 8:07 a.m.: "

*** ALERT *** POTENTIAL -- POTENTIAL for Severe cold outbreak DEC 6-10 for Entire Eastern half of the US ..2 waves of serious cold FIRST wave of cold DEC 5-6-7... 2nd wave of serious Cold DEC 9-10-11."

I'm sure he is leaning on the Euro which is probably the right call...but boy if the GFS is correct it should be fun to read him backing out of this one.

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I'm sure he is leaning on the Euro which is probably the right call...but boy if the GFS is correct it should be fun to read him backing out of this one.

I'd rather lean with him! thumbsupsmileyanim.gif I'm ready for some real cold!

I'm averaging 52.5 for November so far:

2011 - 52.5

2010 - 51.1

2009 - 52.3

2008 - 49.9

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USA was still injecting natural gas up to Thanksgiving, when we are normally well into withdrawal season. We've had a few cold mornings, but overall Novie has been mild.

What super warm November is he talking about? unsure.gif

Regarding that polar pig Euro, I'd like to wait for another run. Ensembles hang it back a bit. Regarding the +PNA, remember all else equal that is cool and unsettled in the Southeast. NAO just a bonus for snow lovers. Reality is that with a +PNA Southeast can keep getting closed lows sneaking in from the Southwest under the West ridge. Right under the low sees the snow. Trowels, like the one that set up Tuesday over east Ark north Miss and west Tenn, can bring the enhanced snow burst. Otherwise, continue mountain snow and valley cold rain; and, be happy for those that get trowel'ed. Enjoy!

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Regarding that polar pig Euro, I'd like to wait for another run. Ensembles hang it back a bit. Regarding the +PNA, remember all else equal that is cool and unsettled in the Southeast. NAO just a bonus for snow lovers. Reality is that with a +PNA Southeast can keep getting closed lows sneaking in from the Southwest under the West ridge. Right under the low sees the snow. Trowels, like the one that set up Tuesday over east Ark north Miss and west Tenn, can bring the enhanced snow burst. Otherwise, continue mountain snow and valley cold rain; and, be happy for those that get trowel'ed. Enjoy!

Hopefully we can because the GFS is looking just kinda blah for winter weather in the Southeast. Should be interesting to see what the Euro says today.

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